Uly.me

cloud engineer

list

AWS List of Auto Scaling Groups

Here’s a script to list Auto Scaling Groups from multiple AWS accounts. Accounts are in your AWS profiles.

#!/bin/bash
file='results-aws-asg.txt'
> $file
declare -a account=("default" "account-1" "account-2" "account-3" "account-4" "account-5")
declare -a region=("us-east-1" "us-east-2" "us-west-1" "us-west-2")
for i in "${account[@]}"
do
    echo '----------------------' >> $file
    echo 'Account: '$i >> $file
    for j in "${region[@]}"
    do
        echo 'Region: '$j >> $file
        aws autoscaling describe-auto-scaling-groups \
        --query "AutoScalingGroups[].[AutoScalingGroupName,LaunchConfigurationName]" \
        --profile $i \
        --region $j \
        --output text >> $file
    done
done

AWS List Account Aliases

Here’s how to list account aliases. I have four profiles in my credentials. I’m looping through all four and printing the aliases.

#!/bin/bash
file='results-aws-account-aliases.txt'
> $file
declare -a account=("default" "one" "two" "three")
for i in "${account[@]}"
do
    echo '----------------------' >> $file
    echo 'Account: '$i >> $file
    aws iam list-account-aliases \
    --profile $i 
done

Linux Screen

Just documenting the Linux Screen command.

Install screen first.

yum install screen
dnf install screen
apt install screen
zypper install screen

Start a new screen.

screen -S one
screen -S two
screen -S three

Detach from screen.

Ctrl+a+d

List active screens.

screen -ls 
There is a screen on:
        15575.one   (Detached)
        15581.two   (Detached)
        15593.three (Detached)
1 Socket in /var/run/screen/S-root.

Reattach to an existing screen.

screen -r one
screen -r two
screen -r three

If there’s only one active screen, you can run screen -r without the name.

screen -r

To exit or quit a screen, reattach and run exit.

screen -r three
# exit
[screen is terminating]

Saving and Restoring iptables

iptables can be saved or loaded from a file. Here’s a way to do it.

Saving to a file

# Debian/Ubuntu
iptables-save > /etc/iptables/rules.v4
# Redhat/Centos/Rocky
iptables-save > /etc/sysconfig/iptables

Loading from a file

# Debian/Ubuntu
iptables-restore > /etc/iptables/rules.v4
# Redhat/Centos/Rocky
iptables-restore > /etc/sysconfig/iptables

Listing rules

iptables -L

GCP List of BMS Servers

Here’s how to list Bare Metal Servers in Google Cloud Platform via gcloud.

gcloud bms instances list --region REGION --project PROJECT

Result

NAME            ID                 PROJECT         REGION       MACHINE_TYPE           CLIENT_IPS    PRIVATE_IPS                    STATE
server-001      at-xxxxxxx-svr001  project-01      us-central1  o2-ultramem-896-metal  10.0.0.1      192.168.253.1,192.168.252.1    RUNNING
server-002      at-xxxxxxx-svr002  project-02      us-central1  o2-ultramem-896-metal  10.0.0.2      192.168.253.2,192.168.252.2    RUNNING

Obviously you can see the same from GCP’s Console.

History Without Line Numbers

Here’s how to display history without the line numbers.

history -w /dev/stdout

Result

cd /etc/httpd/conf
view httpd.conf 
vim wiki.conf 
vim ssl.conf

Python Boto3 S3 List Objects

How to list S3 objects using Python Boto3

import boto3
from sys import argv
bucket=argv[1]
s3 = boto3.resource('s3')
mybucket = s3.Bucket(bucket)
def list_buckets():
    print("List of Buckets: ")
    for bucket in s3.buckets.all():
        print(bucket.name)
def list_files():
    print("Buckets: The objects in the \"" + bucket + "\" buckets are ... ")
    for files in mybucket.objects.all():
        print(files.key)
def main():
    #list_buckets()
    list_files()
if __name__ == "__main__":
    main()

Running command

$ python test.py bucket-name    # with python
$ ./test.py bucket-name         # without python

Results

Buckets: The objects in the "bucket-name" are ....
abc.txt
def.txt

GCP Create Scheduled Snapshots

How to create scheduled snapshots in GCP.

gcloud compute resource-policies create snapshot-schedule hourly \
--description "my hourly schedule" \
--max-retention-days 7 \
--start-time 00:00 \
--hourly-schedule 1 \
--region us-central1 \
--on-source-disk-delete keep-auto-snapshots \
--storage-location US

Add snapshot schedule to a disk.

gcloud compute disks add-resource-policies disk-name \
--resource-policies hourly \
--zone us-central1-a
gcloud compute disks create disk-name \
--resource-policies hourly \
--zone us-central1-a

List snapshot schedules.

gcloud compute resource-policies list

Describe snapshot schedule.

gcloud compute resource-policies describe hourly